System and method for reducing memory requirements of firmware

Abstract

A mechanism for making increased amounts of firmware available to a computer pre-boot is discussed. To increase the amount of firmware available pre-boot, a design decision is made during the build process as to which segments of the firmware need to be placed on the ROM part and which segments of the firmware can be located elsewhere. The segments of the firmware that are stored remotely from the ROM are referred to as “virtual ROM modules”. Each of the virtual ROM modules is assigned a generated unique identifier, and a “message digest” is constructed for each module using an algorithm such as MD5 or SHA-1. In the software build of the ROM image, the message digest-unique identifier pair created for each Virtual ROM module is used as a logical pointer for the virtual module. Additionally, a search path variable is placed into the ROM image in non-volatile storage. The search path provides for one or more locations in which to look for the Virtual ROM modules, and may be updated at a later point in time.

Description

RELATED APPLICATIONS [0001] The present invention claims the benefit of and priority to a United States provisional application entitled “System and Method for Reducing Memory Requirements of Firmware and Providing Secure Updates and Storage Areas for Firmware” filed Feb. 2, 2005, U.S. Application No. 60 / 649,486, and is related to pending United States Applications entitled “System and Method for Updating Firmware in a Secure Manner” filed Feb. 1, 2006, and “System and Method for Securely Storing Firmware”, filed Feb. 1, 2006.FIELD OF THE INVENTION [0002] The illustrative embodiment of the present invention relates generally to firmware that performs POST on a PC, including BIOS firmware, and more particularly to reducing memory requirements of firmware, securely storing firmware, and updating firmware in a secure manner. BACKGROUND [0003] In recent years, there has been an increased demand for larger amounts of firmware code to be made available to PC's pre-boot. Firmware is softwa...

AI Technical Summary

Benefits of technology

[0006] In one aspect of the present invention a method for reducing the memory requirements of firmware stored in an electronic device includes the step of dividing a firmware image to create multiple virtual ROM modules. The multiple virtual ROM modules are stored in at least one location outside a ROM image located on the electronic device. The method additionally includes a reference for each of the multiple virtual ROM modules in a build of firmware placed in the ROM image. Each reference includes a message digest and a unique identifier for an associated virtual ROM module. The method also retrieves a selected one of the multiple virtual ROM modules during pre-boot using the unique identifier in the reference associated with the selected one of the multiple virtual ROM modules. The method further verifies the selected one of the multiple virtual ROM modules during pre-boot using the message digest in the reference associated with the selected one of the multiple virtual ROM modules.

[0008] In an aspect of the present invention a method for reducing the memory requirements of firmware stored in an electronic device includes the step of dividing a firmware image to create a virtual ROM module that is stored in a location outside a ROM image located on the electronic device. The method also includes a reference for the virtual ROM module in a build of firmware placed in the ROM image. The reference includes a message digest and a unique identifier for the virtual ROM module. Additionally, the method retrieves the virtual ROM module during pre-boot using the unique identifier in the reference associated with the virtual ROM module.

Problems solved by technology

Unfortunately there are a number of issues associated with conventional methods of using firmware.

The increased demand to make larger amounts of firmware code available pre-boot has not been fully met by increases in the storage available on a ROM or Flash part due to the fact that there are strong incentives in industry to keep the cost of the hardware for a PC down.

Current methods of updating firmware stored on a Flash part include a risk to the future operability of the computer, since a failure to complete the update successfully can cause the computer to become inoperable.

Allowing such updates also imposes a small security risk in that the Flash firmware often has complete access to the internals of the computer.

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